4.9-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Gleixner tglx@linutronix.de
commit 545401f4448a807b963ff17b575e0a393e68b523 upstream
To support force disabling of SMT it's required to know the number of thread siblings early. detect_ht() cannot be called before the APIC driver is selected, so split out the part which initializes smp_num_siblings.
Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Konrad Rzeszutek Wilk konrad.wilk@oracle.com Acked-by: Ingo Molnar mingo@kernel.org Signed-off-by: David Woodhouse dwmw@amazon.co.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kernel/cpu/common.c | 24 ++++++++++++++---------- arch/x86/kernel/cpu/cpu.h | 1 + 2 files changed, 15 insertions(+), 10 deletions(-)
--- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -606,32 +606,36 @@ static void cpu_detect_tlb(struct cpuinf tlb_lld_4m[ENTRIES], tlb_lld_1g[ENTRIES]); }
-void detect_ht(struct cpuinfo_x86 *c) +int detect_ht_early(struct cpuinfo_x86 *c) { #ifdef CONFIG_SMP u32 eax, ebx, ecx, edx; - int index_msb, core_bits;
if (!cpu_has(c, X86_FEATURE_HT)) - return; + return -1;
if (cpu_has(c, X86_FEATURE_CMP_LEGACY)) - return; + return -1;
if (cpu_has(c, X86_FEATURE_XTOPOLOGY)) - return; + return -1;
cpuid(1, &eax, &ebx, &ecx, &edx);
smp_num_siblings = (ebx & 0xff0000) >> 16; + if (smp_num_siblings == 1) + pr_info_once("CPU0: Hyper-Threading is disabled\n"); +#endif + return 0; +}
- if (!smp_num_siblings) - smp_num_siblings = 1; +void detect_ht(struct cpuinfo_x86 *c) +{ +#ifdef CONFIG_SMP + int index_msb, core_bits;
- if (smp_num_siblings == 1) { - pr_info_once("CPU0: Hyper-Threading is disabled\n"); + if (detect_ht_early(c) < 0) return; - }
index_msb = get_count_order(smp_num_siblings); c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb); --- a/arch/x86/kernel/cpu/cpu.h +++ b/arch/x86/kernel/cpu/cpu.h @@ -46,6 +46,7 @@ extern const struct cpu_dev *const __x86
extern void get_cpu_cap(struct cpuinfo_x86 *c); extern void cpu_detect_cache_sizes(struct cpuinfo_x86 *c); +extern int detect_ht_early(struct cpuinfo_x86 *c);
extern void x86_spec_ctrl_setup_ap(void);